Processes for preparing β-diketone compound, metal complex thereof and metallic compound

Abstract

Disclosed is a process for preparing a β-diketone compound such as 2,6-dimethyl-3,5-heptanedione, which comprises reacting an ester compound such as an alkyl isobutyrate with a ketone compound such as 3-methylbutanone in the presence of an alkali metal alkoxide as a catalyst. The process comprises a step 1 in which an ester compound CR 1 R 2 R 3 COOQ is reacted with a ketone compound CR 4 R 5 R 6 COCH 2 R 7 using an alkali metal alkoxide catalyst to give a β-diketone compound CR 1 R 2 R 2 R 3 COCHR 4 R 5 R 6 . (In the formulae, R 7 is hydrogen or an alkyl group of 1 to 4 carbon atoms while others are each independently hydrogen or an alkyl group of 1 to 3 carbon atoms, and at least one of R 1 to R 6 is hydrogen.)

1. A process for preparing a β-diketone compound represented by the following formula (3), comprising a step 1 of reacting an ester compound represented by the following formula (1) with a ketone compound represented by the following formula (2) in the presence of an alkali metal alkoxide catalyst, in at least one solvent selected from liquid amide having no hydrogen at the α-position relative to the carbonyl group and liquid urea having no hydrogen at the α-position relative to the carbonyl group,
   CR 1 R 2 R 3 COOQ  (1) 
 
       wherein R 1  to R 3  are each independently hydrogen or an alkyl group of 1 to 3 carbon atoms, and Q is an alkyl group,
   CR 4 R 5 R 6 COCH 2 R 7   (2) 
 
       wherein R 4  to R 6  are each independently hydrogen or an alkyl group of 1 to 3 carbon atoms, and R 7  is hydrogen or an alkyl group of 1 to 4 carbon atoms,
   CR 1 R 2 R 3 COCHR 7 COCR 4 R 5 R 6   (3) 
 
       wherein R 1  to R 7  have the same meanings as defined above and at least one of R 1  to R 6  is hydrogen. 
     
     
       2. The process as claimed in  claim 1 , wherein the compound represented by the formula (1) is an alkyl isobutyrate, the compound represented by the formula (2) is 3-methylbutanone, and the compound represented by the formula (3) is 2,6-dimethyl-3,5-heptanedione. 
     
     
       3. The process as claimed in  claim 2 , wherein the solvent is N,N-dimethylformamide and/or 1,3-dimethyl-2-imidazolidinone. 
     
     
       4. The process as claimed in  claim 2 , wherein the amount of the solvent used is in the range of 3 to 30 times by mass based on the 3-methylbutanone. 
     
     
       5. The process as claimed in  claim 2 , wherein the alkali metal of the alkali metal alkoxide catalyst is sodium or potassium. 
     
     
       6. The process as claimed in  claim 5 , wherein the alcohol portion of the alkali metal alkoxide catalyst is a tertiary alcohol. 
     
     
       7. The process as claimed in  claim 2 , wherein the amount of the alkali metal alkoxide catalyst used is in the range of 1 to 10 times by mol based on the 3-methylbutanone. 
     
     
       8. The process as claimed in  claim 2 , comprising a step 1 of synthesizing 2,6-dimethyl-3,5-heptanedione by reacting the alkyl isobutyrate with the 3-methylbutanone in the presence of the alkali metal alkoxide catalyst and a step 2 of adding an acid to the reaction solution of 2,6-dimethyl-3,5-heptanedione to perform neutralization and adding water to the solution to separate the solution into two layers and thereby isolate the 2,6-dimethyl-3,5-heptanedione as an oil layer. 
     
     
       9. The process as claimed in  claim 8 , wherein the acid is at least one acid selected from sulfuric acid, hydrochloric acid and nitric acid. 
     
     
       10. The process as claimed in  claim 8 , comprising recovering the alkyl isobutyrate, 3-methylbutanone and the solvent from the oil layer containing 2,6-dimethyl-3,5-heptanedione by distillation separation and reusing them in the reaction.